Defying government warnings to stay away, more than 1,000 supporters show up for her arrival at court

BANGKOK—Tension is rising in Thailand as former Prime Minister Yingluck Shinawatra enters the final stages of a trial accusing her of mismanaging a multibillion-dollar rice-subsidy program.

Defying warnings by the ruling junta to stay away, more than 1,000 of Ms. Yingluck’s supporters—watched over by 300 police officers—gathered Tuesday outside the Supreme Court as she arrived to make her closing statement. A verdict is due Aug. 25.